Windows installer fixes

[Thiago Macieira]

This patch series includes the fixes I needed to do to create a
working Windows installer, which, in addition:
 a) installs Subsurface
 b) Subsurface runs
 c) the maps show

I haven't tested anything further. You can check out this build by
downloading from:
  http://macieira.org/~thiago/subsurface-3.9-156-g174cbf1ba276.exe

Once we have the networking code in, we'll need to adapt the
deployment & install rules to include deployment of the two OpenSSL
libraries. Qt always dynamically opens them, so they don't show up on
the win-ldd.pl script output. But this is post-beta.